package com.atguigu.gulimall.seckill.service.impl;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.atguigu.common.to.mq.SeckillOrderTo;
import com.atguigu.common.utils.R;
import com.atguigu.common.vo.MemberResponseVo;
import com.atguigu.gulimall.seckill.feign.CouponFeignService;
import com.atguigu.gulimall.seckill.feign.ProductFeignService;
import com.atguigu.gulimall.seckill.interceptor.LoginUserInterceptor;
import com.atguigu.gulimall.seckill.service.SeckillService;
import com.atguigu.gulimall.seckill.to.SeckillSkuRedisTo;
import com.atguigu.gulimall.seckill.vo.SeckillSessionWithSkusVo;
import com.atguigu.gulimall.seckill.vo.SkuInfoVo;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.redisson.api.RSemaphore;
import org.redisson.api.RedissonClient;
import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.BoundHashOperations;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import java.util.Date;
import java.util.List;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

/**
 * @Description:
 * @Created: with IntelliJ IDEA.
 * @author: weichen
 * @createTime: 2020-07-09 19:29
 **/

@Slf4j
@Service
public class SeckillServiceImpl implements SeckillService {

    @Autowired
    private StringRedisTemplate redisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    @Autowired
    private CouponFeignService couponFeignService;

    @Autowired
    private ProductFeignService productFeignService;

    @Autowired
    private RabbitTemplate rabbitTemplate;

    private final String SESSION_CACHE_PREFIX = "seckill:sessions:";

    private final String SECKILL_CHARE_PREFIX = "seckill:skus";

    private final String SKU_STOCK_SEMAPHORE = "seckill:stock:";    //+商品随机码

    @Override
    public void uploadSeckillSkuLatest3Days() {

        //1、扫描最近三天的商品需要参加秒杀的活动
        R lates3DaySession = couponFeignService.getLates3DaySession();
        if (lates3DaySession.getCode() == 0) {
            //上架商品
            List<SeckillSessionWithSkusVo> sessionData = lates3DaySession.getData("data", new TypeReference<List<SeckillSessionWithSkusVo>>() {
            });
            if(sessionData !=null){
                //缓存到Redis
                //1、缓存活动信息
                saveSessionInfos(sessionData);

                //2、缓存活动的关联商品信息
                saveSessionSkuInfo(sessionData);
            }
        }

    }

    public List<SeckillSkuRedisTo> getCurrentSeckillSkusBlockHandler(BlockException ex){
        log.error("getCurrentSeckillSkus方法被限流了，",ex);
        return null;
    }

    @SentinelResource(value="getCurrentSeckillSkus",blockHandler = "getCurrentSeckillSkusBlockHandler")
    @Override
    public List<SeckillSkuRedisTo> getCurrentSeckillSkus() {
        //1、确定当前属于哪个秒杀场次
        long currentTime = System.currentTimeMillis();

        //从Redis中查询到所有key以seckill:sessions开头的所有数据
        Set<String> keys = redisTemplate.keys(SESSION_CACHE_PREFIX + "*");
        for (String key : keys) {
            //seckill:sessions:1594396764000_1594453242000
            String replace = key.replace(SESSION_CACHE_PREFIX, "");
            String[] s = replace.split("_");
            //获取存入Redis商品的开始时间
            long startTime = Long.parseLong(s[0]);
            //获取存入Redis商品的结束时间
            long endTime = Long.parseLong(s[1]);

            //判断是否是当前秒杀场次
            if (currentTime >= startTime && currentTime <= endTime) {
                //2、获取这个秒杀场次需要的所有商品信息
                List<String> range = redisTemplate.opsForList().range(key, -100, 100);
                BoundHashOperations<String, String, String> hasOps = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);
                assert range != null;
                List<String> listValue = hasOps.multiGet(range);
                if (listValue != null && listValue.size() >= 0) {

                    List<SeckillSkuRedisTo> collect = listValue.stream().map(item -> {
                        String items = (String) item;
                        SeckillSkuRedisTo redisTo = JSON.parseObject(items, SeckillSkuRedisTo.class);
                        // redisTo.setRandomCode(null);当前秒杀开始需要随机码
                        return redisTo;
                    }).collect(Collectors.toList());
                    return collect;
                }
                break;
            }
        }
        return null;
    }

    @Override
    public SeckillSkuRedisTo getSkuSeckilInfo(Long skuId) {
        //1、找到所有需要秒杀的商品的key信息---seckill:skus
        BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);

        //拿到所有的key
        Set<String> keys = hashOps.keys();
        if (keys != null && keys.size() > 0) {
            //4-45 正则表达式进行匹配
            String reg = "\\d_" + skuId;
            for (String key : keys) {
                //如果匹配上了
                if (Pattern.matches(reg,key)) {
                    //从Redis中取出数据来
                    String redisValue = hashOps.get(key);
                    //进行序列化
                    SeckillSkuRedisTo redisTo = JSON.parseObject(redisValue, SeckillSkuRedisTo.class);

                    //随机码
                    Long currentTime = System.currentTimeMillis();
                    Long startTime = redisTo.getStartTime();
                    Long endTime = redisTo.getEndTime();
                    //如果当前时间大于等于秒杀活动开始时间并且要小于活动结束时间
                    if (currentTime >= startTime && currentTime <= endTime) {
                        return redisTo;
                    }
                    redisTo.setRandomCode(null);
                    return redisTo;
                }
            }
        }
        return null;
    }

    @Override
    public String kill(String killId, String key, Integer num) {
        long s1 = System.currentTimeMillis();
        MemberResponseVo user = LoginUserInterceptor.threadLocal.get();

        //1、获取当前秒杀商品的详细信息从Redis中获取
        BoundHashOperations<String, String, String> boundHashOps = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);
        String skuStr = boundHashOps.get(killId);
        if(!StringUtils.isEmpty(skuStr)){
            //(合法性效验)
            SeckillSkuRedisTo skuRedisTo = JSON.parseObject(skuStr, SeckillSkuRedisTo.class);
            Long startTime = skuRedisTo.getStartTime();
            Long endTime = skuRedisTo.getEndTime();
            long now = new Date().getTime();

            //判断当前这个秒杀请求是否在活动时间区间内(效验时间的合法性)
            if(now>=startTime && now<=endTime){
                String randomCode = skuRedisTo.getRandomCode();
                Long skuId = skuRedisTo.getSkuId();
                Long  promotionSessionId= skuRedisTo.getPromotionSessionId();//活动场次id
                String promotionId_skuId=promotionSessionId+"_"+skuId;

                //2、效验随机码和商品id
                if(randomCode.equals(key) && promotionId_skuId.equals(killId)){
                    Integer seckillLimit = skuRedisTo.getSeckillLimit();

                    //3、验证购物数量是否合理和库存量是否充足
                    if(num<=seckillLimit){

                        //4、验证这个人是否已经买过了（幂等性处理）,如果秒杀成功，就去占位。userId-sessionId-skuId
                        //SETNX 原子性处理
                        long ttl = endTime - now;
                        Boolean ifAbsent = redisTemplate.opsForValue().setIfAbsent(user.getId() + "-" + promotionSessionId + "-" + skuId, String.valueOf(num),
                                ttl, TimeUnit.MILLISECONDS);
                        //TODO 这里有问题，如果没有抢到信号量，或者发送MQ失败，用户应该可以再次抢购。但是redis占位，就不能再抢了。
                        if(ifAbsent){
                            //占位成功说明从来没有买过,分布式锁(获取信号量-1)
                            //获取信号量
                            RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE+randomCode);
                            try {
                                boolean tryAcquire = semaphore.tryAcquire(num,100,TimeUnit.MILLISECONDS);
                                if(tryAcquire){
                                    //秒杀成功 下单
                                    //TODO 发送MQ.整个方法（包含网络传输）耗时50ms，单线程下，一秒可以执行20并发量。
                                    // 当tomcat并发数设置为500时，单机并发量支持1w。
                                    String orderSn = IdWorker.getTimeId();
                                    SeckillOrderTo orderTo=new SeckillOrderTo();
                                    orderTo.setOrderSn(orderSn);
                                    orderTo.setMemberId(user.getId());
                                    orderTo.setSkuId(skuId);
                                    orderTo.setSeckillPrice(skuRedisTo.getSeckillPrice());
                                    orderTo.setNum(num);
                                    orderTo.setPromotionSessionId(promotionSessionId);
                                    rabbitTemplate.convertAndSend("order-event-exchange","order.seckill.order",orderTo);

                                    return orderSn;
                                }
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                                return null;
                            }
                        }
                    }
                }
            }
        }
        long s3 = System.currentTimeMillis();
        log.info("耗时..." + (s3 - s1));
        return null;
    }

    /**
     * 缓存秒杀活动信息
     * @param sessions
     */
    private void saveSessionInfos(List<SeckillSessionWithSkusVo> sessions) {

        sessions.stream().forEach(session -> {

            //获取当前活动的开始和结束时间的时间戳
            long startTime = session.getStartTime().getTime();
            long endTime = session.getEndTime().getTime();

            //存入到Redis中的key
            String key = SESSION_CACHE_PREFIX + startTime + "_" + endTime;

            if(!redisTemplate.hasKey(key)){
                //获取到活动中所有商品的skuId
                List<String> skuIds = session.getRelationSkus().stream()
                        .map(item ->item.getPromotionSessionId()+"_"+ item.getSkuId().toString()).collect(Collectors.toList());
                redisTemplate.opsForList().leftPushAll(key,skuIds);
            }
        });

    }

    /**
     * 缓存秒杀活动所关联的商品信息
     * @param sessions
     */
    private void saveSessionSkuInfo(List<SeckillSessionWithSkusVo> sessions) {

        sessions.stream().forEach(session -> {
            //准备hash操作，绑定hash
            BoundHashOperations<String, Object, Object> operations = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);
            session.getRelationSkus().stream().forEach(seckillSkuVo -> {
                //生成随机码
                String token = UUID.randomUUID().toString().replace("-", "");
                if(!operations.hasKey(seckillSkuVo.getPromotionSessionId()+"_"+ seckillSkuVo.getSkuId().toString())){
                    //缓存我们商品信息
                    SeckillSkuRedisTo redisTo = new SeckillSkuRedisTo();
                    Long skuId = seckillSkuVo.getSkuId();
                    //1、先查询sku的基本信息，调用远程服务
                    R info = productFeignService.getSkuInfo(skuId);
                    if (info.getCode() == 0) {
                        SkuInfoVo skuInfo = info.getData("skuInfo",new TypeReference<SkuInfoVo>(){});
                        redisTo.setSkuInfo(skuInfo);
                    }

                    //2、sku的秒杀信息
                    BeanUtils.copyProperties(seckillSkuVo,redisTo);

                    //3、设置当前商品的秒杀时间信息
                    redisTo.setStartTime(session.getStartTime().getTime());
                    redisTo.setEndTime(session.getEndTime().getTime());

                    //4、设置商品的随机码（防止恶意攻击）
                    redisTo.setRandomCode(token);

                    //5、使用库存作为分布式信号量 限流！
                    RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + token);
                    //商品可以秒杀的数量作为信号量
                    semaphore.trySetPermits(seckillSkuVo.getSeckillCount());

                    //序列化json格式存入Redis中
                    String seckillValue = JSON.toJSONString(redisTo);
                    operations.put(seckillSkuVo.getPromotionSessionId()+"_"+ seckillSkuVo.getSkuId().toString(),seckillValue);
                }
            });
        });
    }



}
